Multi-linked device having a reinforcing member

ABSTRACT

A steerable multi-linked device may include a first multi-linked mechanism and a second multi-linked mechanism. At least one of the first multi-linked mechanism and the second multi-linked mechanism may include a first link, a plurality of intermediate links, a second link movably coupled to a second one of the intermediate links and a reinforcing member. A first one of the intermediate links may be movably coupled to the first link, and the reinforcing member may extend from a first end of a third one of the intermediate links toward a second end of the third one of the intermediate links.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and is a continuation of U.S.patent application Ser. No. 12/038,560, filed on Feb. 27, 2008, whichclaims priority to U.S. patent application Ser. No. 60/891,881, filed onFeb. 27, 2007, the disclosures of which are incorporated herein byreference in their entireties.

Not Applicable

BACKGROUND

This application discloses an invention that is related, generally andin various embodiments, to a steerable multi-linked device having areinforcing member.

SUMMARY

A steerable multi-linked device may include a first multi-linkedmechanism and a second multi-linked mechanism. At least one of the firstmulti-linked mechanism and the second multi-linked mechanism may includea first link, a plurality of intermediate links, a second link movablycoupled to a second one of the intermediate links and a reinforcingmember. A first one of the intermediate links may be movably coupled tothe first link, and the reinforcing member may extend from a first endof a third one of the intermediate links toward a second end of thethird one of the intermediate links.

BRIEF DESCRIPTION OF DRAWINGS

Various embodiments of the invention are described herein by way ofexample in conjunction with the following figures.

FIGS. 1A and 1B illustrate various embodiments of a steerablemulti-linked device;

FIG. 2 illustrates various embodiments of a core mechanism of the deviceof FIG. 1;

FIGS. 3A-3C illustrate various embodiments of a proximal link of thecore mechanism;

FIGS. 4A-4C illustrate various embodiments of an intermediate link ofthe core mechanism;

FIGS. 5A-5C illustrate various embodiments of a distal link of the coremechanism;

FIG. 6 illustrates various embodiments of a sleeve mechanism of thedevice of FIG. 1;

FIGS. 7A-7C illustrate various embodiments of a proximal link of thesleeve mechanism;

FIGS. 8A-8C illustrate various embodiments of an intermediate link ofthe sleeve mechanism;

FIGS. 9A-9D illustrate various embodiments of a distal link of thesleeve mechanism;

FIG. 10 illustrates various embodiments of a motion sequence of thedevice of FIG. 1;

FIG. 11 illustrates various embodiments of a steerable multi-linkeddevice traversing a path having tight curvatures;

FIG. 12 illustrates various embodiments of a portion of a steerablemulti-linked device having one or more reinforcing members;

FIG. 13 illustrates an exemplary mechanical limit according to variousembodiments;

FIG. 14 illustrates an exemplary mechanical limit according to variousembodiments.

DETAILED DESCRIPTION

It is to be understood that at least some of the figures anddescriptions of the invention have been simplified to focus on elementsthat are relevant for a clear understanding of the invention, whileeliminating, for purposes of clarity, other elements that those ofordinary skill in the art will appreciate may also comprise a portion ofthe invention. However, because such elements are well known in the art,and because they do not necessarily facilitate a better understanding ofthe invention, a description of such elements is not provided herein.

According to various embodiments, the invention described herein may beutilized to control movement of a multi-linked device such as thesteerable multi-linked device described herein. For ease of explanationpurposes, the invention will be described in the context of its use withvarious embodiments of the steerable multi-linked device describedherein. However, one skilled in the art will appreciate that theinvention may be utilized with other types of multi-linked devices.

FIGS. 1A and 1B illustrate various embodiments of a steerablemulti-linked device 10. According to various embodiments, the steerablemulti-linked device may be a snake robot, a continuum robot or the like.Various embodiments of the device 10 may be utilized for medicalprocedures (e.g., as a robotic bore, positioning device, ablation tool,camera or instrument support, or guidance system for minimally invasiveprocedures), for surveillance applications, for inspection applications,for search and rescue applications, etc. For purposes of clarity only,the utility of the device 10 will be described hereinbelow in thecontext of its applicability to medical procedures. However, a personskilled in the art will appreciate that the device 10 can be utilized ina variety of different applications.

The device 10 comprises a first mechanism 12 and a second mechanism 14.According to various embodiments, a mechanism may be a snake robot, acontinuum robot or the like. According to various embodiments, thesecond mechanism 14 is structured and arranged to receive and surroundthe first mechanism 12 as shown in FIG. 1B. Thus, the first mechanismand second mechanism may be concentric. For such embodiments, the firstmechanism 12 may be considered the inner mechanism or the coremechanism, and the second mechanism 14 may be considered the outermechanism or the sleeve mechanism. According to other embodiments, thefirst and second mechanisms 12, 14 may be structured and arranged tohave a relationship other than a concentric relationship. For example,one skilled in the art will appreciate that, according to variousembodiments, the first and second mechanisms 12, 14 may be structuredand arranged to operate in a side-by-side arrangement, where the firstmechanism 12 operates adjacent to the second mechanism 14. According tovarious embodiments, additional and/or alternate configurations may beused within the scope of this disclosure. According to variousembodiments, a three-dimensional space 240 may be provided between thefirst and second mechanisms. This space will be described in more detailbelow.

As described in more detail hereinbelow, the first mechanism 12 mayoperate in either a rigid mode or a limp mode, the second mechanism 14may operate in either a rigid mode or a limp mode, and the first andsecond mechanisms 12, 14 may operate independent of one another. Boththe first mechanism 12 and the second mechanism 14 may be steerablemechanisms. Accordingly, it will be appreciated that the device 10 maybe utilized to navigate a luminal space as well as any three-dimensionalpath within an intracavity space. According to various embodiments, thedevice 10 may advance by alternating the operation of the firstmechanism 12 and the second mechanism 14 between a limp mode and a rigidmode.

According to various embodiments, the device 10 may also comprise one ormore cables. According to various embodiments, one or more of the cablesmay be steering cables and/or tensioning cables. For example, the devicemay include three steering cables and one tensioning cables.

FIG. 2 illustrates various embodiments of the first mechanism 12 of thedevice 10. The first mechanism 12 is a multi-linked mechanism andincludes a first end 24 and a second end 26. The first end 24 may beconsidered the proximal end and the second end 26 may be considered thedistal end. The first mechanism 12 may comprise a first link 28, asecond link 30, and one or more intermediate links 32 between the firstand second links 28, 30. The first link 28 may be considered theproximal link, and the second link 30 may be considered the distal link.

FIGS. 3A-3C illustrate various embodiments of the first link 28 (innerproximal link) of the first mechanism 12. The first link 28 includes afirst end 34 and a second end 36, and defines a longitudinal axis 38that passes through the center of the first end 34 and the center of thesecond end 36 as shown in FIG. 3B. The first link 28 may be fabricatedfrom any suitable material. According to various embodiments, the firstlink 28 is fabricated from a fiber reinforced material such as, forexample, G10/FR4 Garolite®. The first link 28 has a generallycylindrical shaped exterior and is described in more detail hereinbelow.

The first link 28 comprises a first portion 40 and a second portion 42.The first portion 40 may be considered the proximal portion and thesecond portion 42 may be considered the distal portion. The firstportion 40 may be fabricated integral with the second portion 42. Thefirst portion 40 has a cylindrical shaped exterior, and extends from thefirst end 34 of the first link 28 toward the second end 36 of the firstlink 28. According to various embodiments, the diameter of the firstportion 40 may be on the order of approximately 6.35 millimeters. Othersizes are possible.

The second portion 42 has a generally cylindrically shaped exterior,with other features described below. The second portion 42 has acylindrically shaped exterior where it contacts the first portion 40,and tapers toward the second end 36 of the first link 28. The secondportion 42 may be shaped in the form of a generally segmented hemisphereat the second end 36 of the first link 28. According to variousembodiments, the diameter of the second portion 42 may be on the orderof approximately 4.75 millimeters where it contacts the first portion40. Other sizes are possible.

The second portion 42 comprises a first surface 44. The first surface 44may be considered the outer surface of the second portion 42. The secondportion 42 defines a first groove 46 parallel to the longitudinal axis38 along the first surface 44, a second groove 48 parallel to thelongitudinal axis 38 along the first surface 44, and a third groove 50parallel to the longitudinal axis 38 along the first surface 44. Each ofthe first, second and third grooves 46, 48, 50 extend along the firstsurface 44 toward the second end 36 of the first link 28. The first,second and third grooves 46, 48, 50 may be semi-tubular shaped and maybe evenly spaced about the first surface 44 of the second portion 42 ofthe first link 28 as shown in FIG. 3C. According to various embodiments,the first, second, and third grooves 46, 48, 50 may be configured in theshape of a segmented cylinder. The size of each of the grooves 46, 48,50 may be identical to one another or may be different from one another.For example, according to various embodiments, the first and secondgrooves 46, 48 may be configured as segments of a cylinder having adiameter on the order of approximately 1.25 millimeters, and the thirdgroove 50 may be configured as a segment of a cylinder having a diameteron the order of approximately 2.50 millimeters. The length of the firstlink 28 may be on the order of approximately 65 millimeters. However,one skilled in the art will appreciate that the length or diameter ofthe first link 28 can vary based on the application.

The first link 28 also defines a passage 52 extending from the first end34 to the second end 36 along the longitudinal axis 38 as shown in FIG.3B. The passage 52 is of a size sufficient to allow at least one cableto pass therethrough. According to various embodiments, the passage 52may be of a sufficient size to allow a tensioning cable to passtherethrough. According to various embodiments, the passage 52 isgenerally configured as a complex shape that comprises a combination ofa first cylinder 54 that extends from the first end 34 toward the secondend 36, and a second cylinder 56 that extends from the first cylinder 54toward the second end 36. The diameter of the first cylinder 54 islarger than the diameter of the second cylinder 56. For example,according to various embodiments, the first cylinder 54 may have adiameter on the order of approximately 3.20 millimeters and the secondcylinder 56 may have a diameter on the order of approximately 1.50millimeters. Other sizes are possible.

FIGS. 4A-4C illustrate various embodiments of one of the intermediatelinks 32 (inner intermediate link) of the first mechanism 12. Theintermediate link 32 is representative of the other intermediate links32. The intermediate link 32 includes a first end 58 and a second end60, and defines a longitudinal axis 62 that passes through the center ofthe first end 58 and the center of the second end 60 as shown in FIG.4B. The intermediate link 32 may be fabricated from any suitablematerial. According to various embodiments, the intermediate link 32 isfabricated from a fiber reinforced material such as, for example,G10/FR4 Garolite®. The intermediate link 32 has a generallybullet-shaped exterior and is described in more detail hereinbelow.

The intermediate link 32 comprises a first portion 64 and a secondportion 66. The first portion 64 may be considered the proximal portionand the second portion 66 may be considered the distal portion. Thefirst portion 64 may be fabricated integral with the second portion 66.The first portion 64 has a generally cylindrical shaped exterior, andextends from the first end 58 of the intermediate link 32 toward thesecond end 60 of the intermediate link 32. According to variousembodiments, the second portion 66 has a generally cylindrically shapedexterior where it contacts the first portion 64, and tapers toward thesecond end 60 of the intermediate link 32. The exterior of the secondportion 66 is configured in the form of a generally segmentedhemisphere. According to various embodiments, the diameter of theintermediate link 32 may be on the order of approximately 4.75millimeters at the first end 58 thereof. The length of the intermediatelink 32 may be on the order of approximately 5.85 millimeters. However,one skilled in the art will appreciate that the length or diameter ofthe intermediate link 32 can vary based on the application.

The intermediate link 32 also comprises a first surface 68 that extendsfrom the first end 58 of the intermediate link 32 to the second end 60of the intermediate link 32. The first surface 68 may be considered theouter surface of the intermediate link 32. The intermediate link 32 alsodefines a first groove 70 parallel to the longitudinal axis 62 along thefirst surface 68, a second groove 72 parallel to the longitudinal axis62 along the first surface 68, and a third groove 74 parallel to thelongitudinal axis 62 along the first surface 68. Each of the first,second and third grooves 70, 72, 74 extend along the first surface 68from the first end 58 of the intermediate link 32 toward the second end60 of the intermediate link 32. The first, second and third grooves 70,72, 74 may be semi-tubular shaped and may be evenly spaced about thefirst surface 68 of the intermediate link 32 as shown in FIG. 4C.According to various embodiments, the first, second, and third grooves70, 72, 74 may be configured in the shape of a segmented cylinder. Thesize of each of the grooves 70, 72, 74 may be identical to one anotheror may be different from one another. For example, according to variousembodiments, the first and second grooves 70, 72 are configured assegments of a cylinder having a diameter on the order of approximately1.75 millimeters at the first end 58 of the intermediate link 32, andthe third groove 74 is configured as a segment of a cylinder having adiameter on the order of approximately 2.50 millimeters at the first end58 of the intermediate link 32. The first, second and third grooves 70,72, 74 are each configured to receive and partially surround any of avariety of tools or instruments (e.g., ablation tools) which may passfrom the first end 24 of the multi-linked device 10 to the second end 26of the multi-linked device 10.

The intermediate link 32 also defines a passage 76 extending from thefirst end 58 to the second end 60 along the longitudinal axis 62 asshown in FIG. 4B. The passage 76 may be of a size sufficient to allowone or more cables to pass therethrough. According to variousembodiments, the passage 76 may be of a size sufficient to allow atensioning cable to pass therethrough. According to various embodiments,the passage 76 is generally configured as a complex shape that comprisesa combination of a first segmented hemisphere 78 that extends from thefirst end 58 toward the second end 60, a second segmented hemisphere 80that extends from the first segmented hemisphere 78 toward the secondend 60, a cylinder 82 that extends from the second segmented hemisphere80 toward the second end 60, and a third segmented hemisphere 84 thatextends from the cylinder 82 to the second end 60 of the intermediatelink 32. According to various embodiments, the first segmentedhemisphere 78 represents a portion of a sphere having a diameter on theorder of approximately 4.75 millimeters, the second segmented hemisphere80 represents a portion of a sphere having a diameter on the order ofapproximately 2.25 millimeters, the cylinder 82 may have a diameter onthe order of approximately 1.0 millimeter, and the third segmentedhemisphere 84 represents a portion of a sphere having a diameter on theorder of approximately 2.25 millimeters. Other sizes are possible.

The first segmented hemisphere 78 of the passage 76 is configured toreceive the second end 36 of the first link 28 when the first link 28 iscoupled to the intermediate link 32. Similarly, for a given intermediatelink 32, the first segmented hemisphere 78 of the passage 76 isconfigured to receive the second end 60 of another intermediate link 32when the other intermediate link 32 is coupled to the given intermediatelink 32. The third segmented hemisphere 84 may serve to reduce thepinching or binding a cable when one intermediate link 32 moves relativeto an adjacent intermediate link 32 coupled thereto. Similarly, when thesecond link 30 is coupled to a given intermediate link 32, the thirdsegmented hemisphere 84 may serve to reduce the pinching or binding of acable when the second link 30 moves relative to the given intermediatelink 32.

With the above described structure, the first link 28 may be coupled tothe intermediate link 32 by seating the second end 36 of the first link28 in the first segmented hemisphere 78 of the passage 76 of theintermediate link 32. As the convex configuration of the second end 36of the first link 28 generally corresponds with the concaveconfiguration of the first segmented hemisphere 78 of the passage 76 ofthe intermediate link 32, the first link 28 may be coupled to theintermediate link 32 such that the longitudinal axis 38 and the first,second and third grooves 46, 48, 50 of the first link 28 arerespectively aligned with the longitudinal axis 62 and the first, secondand third grooves 70, 72, 74 of the intermediate link 32. Theintermediate link 32 may be moved relative to the first link 28 suchthat the longitudinal axis 62 of the intermediate link 32 is not alignedwith the longitudinal axis 38 of the first link 28. According to variousembodiments, the configuration of the first link 28 and the intermediatelink 32 allows for the intermediate link 32 to be moved relative to thefirst link 28 coupled thereto such that the longitudinal axis 38 of thefirst link 28 and the longitudinal axis 62 of the intermediate link 32are up to approximately 25° out of alignment with one another.Similarly, one intermediate link 32 may be coupled to anotherintermediate link 32, and so on, by seating the second end 60 of oneintermediate link 32 in the first segmented hemisphere 78 of the passage76 of another intermediate link 32. As the convex configuration of thesecond end 60 of the intermediate link 32 generally corresponds with theconcave configuration of the first segmented hemisphere 78 of thepassage 76 of the intermediate link 32, the intermediate links 32 may becoupled such that the respective longitudinal axes 62 and the respectivefirst, second and third grooves 46, 48, 50 of the intermediate links 32are aligned. The coupled intermediate links 32 may be moved relative toone another such that the respective longitudinal axes 62 of the coupledintermediate links 32 are not aligned. According to various embodiments,the configuration of the coupled intermediate links 32 allows for oneintermediate link 32 to be moved relative to an adjacent intermediatelink 32 coupled thereto such that the respective longitudinal axes 62are up to approximately 25° out of alignment with one another.

FIGS. 5A-5C illustrate various embodiments of the second link 30 (innerdistal link) of the first mechanism 12. The second link 30 includes afirst end 86 and a second end 88, and defines a longitudinal axis 90that passes through the center of the first end 86 and the center of thesecond end 88 as shown in FIG. 5B. The second link 30 may be fabricatedfrom any suitable material. According to various embodiments, the secondlink 30 is fabricated from a thermoplastic material such as, forexample, Delrin®.

The second link 30 comprises a first portion 92 and a second portion 94.The first portion 92 may be considered the proximal portion and thesecond portion 94 may be considered the distal portion. The firstportion 92 may be fabricated integral with the second portion 94. Thefirst portion 92 has a generally cylindrical shaped exterior, andextends from the first end 86 of the second link 30 toward the secondend 88 of the second link 30. According to various embodiments, thesecond portion 94 has a generally cylindrically shaped exterior where itcontacts the first portion 92, and tapers toward the second end 88 ofthe second link 30. The exterior of the second portion 64 is configuredin the form of a generally segmented cone. According to variousembodiments, the diameter of the second link 30 may be on the order ofapproximately 4.75 millimeters at the first end 86 thereof, and thetaper of the second portion 94 may be at an angle of approximately 30°relative to the exterior of the first portion 92. The length of thesecond link 30 may be on the order of approximately 5.90 millimeters.However, one skilled in the art will appreciate that the length ordiameter of the second link 30 can vary based on the application.

The second link 30 also comprises a first surface 96 that extends fromthe first end 86 of the second link 30 to the second end 88 of thesecond link 30. The first surface 96 may be considered the outer surfaceof the second link 30. The second link 30 also defines a first groove 98parallel to the longitudinal axis 90 along the first surface 96, asecond groove 100 parallel to the longitudinal axis 90 along the firstsurface 96, and a third groove 102 parallel to the longitudinal axis 90along the first surface 96. Each of the first, second and third grooves98, 100, 102 extend along the first surface 96 from the first end 86 ofthe second link 30 toward the second end 88 of the second link 30. Thefirst, second and third grooves 98, 100, 102 may be semi-tubular shapedand may be evenly spaced about the first surface 96 of the second link30 as shown in FIG. 5C. According to various embodiments, the first,second, and third grooves 98, 100, 102 may be configured in the shape ofa segmented cylinder. The size of each of the grooves 98, 100, 102 maybe identical to one another or may be different from one another. Forexample, according to various embodiments, the first and second grooves98, 100 are configured as segments of a cylinder having a diameter onthe order of approximately 1.25 millimeters at the first end 86 of thesecond link 30, and the third groove 102 is configured as a segment of acylinder having a diameter on the order of approximately 2.50millimeters at the first end 86 of the second link 30. The first, secondand third grooves 98, 100, 102 are each configured to receive andpartially surround any of a variety of tools or instruments (e.g.,ablation tools) which may pass from the first end 24 of the multi-linkeddevice 10 to the second end 26 of the multi-linked device 10.

The second link 30 also defines a passage 104 extending from the firstend 86 to the second end 88 along the longitudinal axis 90 as shown inFIG. 5B. The passage 104 may be of a size sufficient to allow at leastone cable to pass therethrough. According to various embodiments, thepassage 104 may be of a size sufficient to allow a tensioning cable topass therethrough. According to various embodiments, the passage 104 isgenerally configured as a complex shape that comprises a combination ofa first segmented hemisphere 106 that extends from the first end 86toward the second end 88, a second segmented hemisphere 108 that extendsfrom the first segmented hemisphere 106 toward the second end 88, and acylinder 110 that extends from the second segmented hemisphere 108 tothe second end 88 of the second link 30. According to variousembodiments, the first segmented hemisphere 106 represents a portion ofa sphere having a diameter on the order of approximately 4.75millimeters, the second segmented hemisphere 108 represents a portion ofa sphere having a diameter on the order of approximately 2.50millimeters, and the cylinder 110 may have a diameter on the order ofapproximately 1.0 millimeter. The first segmented hemisphere 106 of thepassage 104 may be configured to receive the second end 60 of anintermediate link 32 when the intermediate link 32 is coupled to thesecond link 30.

With the above described structure, an intermediate link 32 may becoupled to the second link 30 by seating the second end 60 of theintermediate link 32 in the first segmented hemisphere 106 of thepassage 104 of the second link 30. As the convex configuration of thesecond end 60 of the intermediate link 32 generally corresponds with theconcave configuration of the first segmented hemisphere 106 of thepassage 104 of the second link 30, the intermediate link 32 may becoupled to the second link 30 such that the longitudinal axis 62 and thefirst, second and third grooves 70, 72, 74 of the intermediate link 32are respectively aligned with the longitudinal axis 90 and the first,second and third grooves 98, 100, 102 of the second link 30. The secondlink 30 may be moved relative to the intermediate link 32 coupledthereto such that the respective longitudinal axes 62, 90 are notaligned. According to various embodiments, the configuration of thesecond link 30 allows for an intermediate link 32 coupled thereto to bemoved relative to the second link 30 such that the respectivelongitudinal axes 62, 90 are up to approximately 25° out of alignmentwith one another.

FIG. 6 illustrates various embodiments of the second mechanism 14 of thedevice 10. The second mechanism 14 is a multi-linked mechanism andincludes a first end 120 and a second end 122. The first end 120 may beconsidered the proximal end and the second end 122 may be considered thedistal end. The second mechanism 14 comprises a first link 124, a secondlink 126, and any number of intermediate links 128 between the first andsecond links 124, 126. The first link 124 may be considered the proximallink, and the second link 126 may be considered the distal link.

FIGS. 7A-7C illustrate various embodiments of the first link 124 (outerproximal link) of the second mechanism 14. The first link 124 includes afirst end 130 and a second end 132, and defines a longitudinal axis 134that passes through the center of the first end 130 and the center ofthe second end 132 as shown in FIG. 7B. The first link 124 may befabricated from any suitable material. According to various embodiments,the first link 124 is fabricated from a stainless steel material suchas, for example, 316 stainless steel. The first link 124 has a generallybullet-shaped exterior and is described in more detail hereinbelow.

The first link 124 comprises a first portion 136 and a second portion138. The first portion 136 may be considered the proximal portion andthe second portion 138 may be considered the distal portion. The firstportion 136 may be fabricated integral with the second portion 138. Thefirst portion 136 has a cylindrical shaped exterior, and extends fromthe first end 130 of the first link 124 toward the second end 132 of thefirst link 124. According to various embodiments, the diameter of thefirst portion 136 may be on the order of approximately 12.70millimeters. Other sizes are possible.

The second portion 138 has a generally cylindrically shaped exterior.The second portion 138 has a cylindrically shaped exterior where itcontacts the first portion 136, and tapers toward the second end 132 ofthe first link 124. The second portion 138 may be shaped in the form ofa generally segmented hemisphere at the second end 132 of the first link124. According to various embodiments, the diameter of the secondportion 138 may be on the order of approximately 9.50 millimeters whereit contacts the first portion 136. Other sizes and shapes are possible.

The second portion 138 comprises a first surface 140. The first surface140 may be considered the outer surface of the second portion 138. Thesecond portion 138 defines a first groove 142 along the first surface140, a second groove 144 along the first surface 140, and a third groove146 along the first surface 140. Each of the first, second and thirdgrooves 142, 144, 146 are oblique relative to the longitudinal axis 134and extend along the first surface 140 toward the second end 132 of thefirst link 124. According to various embodiments, each of the grooves142, 144, 146 are oriented at an angle on the order of approximately 15°relative to the longitudinal axis 134. As shown in FIG. 7C, the first,second and third grooves 142, 144, 146 may be evenly spaced about thefirst surface 140 of the first link 124. According to variousembodiments, the first, second, and third grooves 142, 144, 146 may beconfigured in the shape of a segmented cylinder. The size of each of thegrooves 142, 144, 146 may identical to one another or may be differentfrom one another. For example, according to various embodiments, each ofthe grooves 142, 144, 146 are configured as segments of respectivecylinders having diameters on the order of approximately 3.0millimeters. The first, second and third grooves 142, 144, 146 are eachconfigured to facilitate the introduction of various tools orinstruments (e.g., ablation tools) into the multi-linked device 10. Thelength of the first link 124 may be on the order of approximately 18.5millimeters. However, one skilled in the art will appreciate that thelength or diameter of the first link 124 can vary based on theapplication.

The first link 124 also defines a passage 148 extending from the firstend 130 to the second end 132 along the longitudinal axis 134 as shownin FIG. 7B. The passage 148 is of a size sufficient to allow the firstmechanism 12 to pass therethrough. According to various embodiments, thepassage 148 is generally configured as a complex shape that comprises acombination of a segmented cone 150 that extends from the first end 130toward the second end 132, and a cylinder 152 that extends from thesegmented cone 150 to the second end 132 of the first link 124.According to various embodiments, the segmented cone 150 has a diameteron the order of approximately 7.0 millimeters at the first end 130 ofthe first link 124, and may be tapered at an angle on the order ofapproximately 45° relative to the longitudinal axis 134. The cylinder152 may have a diameter on the order of approximately 5.50 millimeters.Other dimensions are possible.

The first link 124 also defines a first through-hole 154, a secondthrough-hole 156, and a third through-hole 158. (See FIG. 7C). The firstthrough-hole 154 is substantially parallel to the longitudinal axis 134,extends from the first portion 136 toward the second end 132, and ispositioned between the passage 148 and the first surface 140. The secondthrough-hole 156 is substantially parallel to the longitudinal axis 134,extends from the first portion 136 to the second end 132, and ispositioned between the passage 148 and the first surface 140. The thirdthrough-hole 158 is substantially parallel to the longitudinal axis 134,extends from the first portion 136 to the second end 132, and ispositioned between the passage 148 and the first surface 140. The first,second and third through-holes 154, 156, 158 are generally cylindricallyshaped. According to various embodiments, the through-holes 154, 156,158 are evenly spaced from one another as shown in FIG. 7C. The size ofeach of the through-holes 154, 156, 158 may be identical to one anotheror may be different from one another. For example, according to variousembodiments, the respective diameters associated with the through-holes154, 156, 158 may each be on the order of approximately 1.20millimeters. The first through-hole 154 is configured to receive andsurround a cable. The second through-hole 156 is configured to receiveand surround a cable. The third through-hole 158 is configured toreceive and surround a cable. The first, second and third through-holes154, 156, 158 may serve as guidepaths for movement of the cables.

FIGS. 8A-8C illustrate various embodiments of one of the intermediatelinks 128 (outer intermediate link) of the second mechanism 14. Theintermediate link 128 is representative of the other intermediate links128. The intermediate link 128 includes a first end 160 and a second end162, and defines a longitudinal axis 164 that passes through the centerof the first end 160 and the center of the second end 162 as shown inFIG. 8C. The intermediate link 128 may be fabricated from any suitablematerial. According to various embodiments, the intermediate link 128 isfabricated from a polymer thermosplastic material such as, for example,polysulfone. The intermediate link 128 has a generally bullet-shapedexterior and is described in more detail hereinbelow.

The intermediate link 128 comprises a first portion 166 and a secondportion 168. The first portion 166 may be considered the proximalportion and the second portion 168 may be considered the distal portion.The first portion 166 may be fabricated integral with the second portion168. The first portion 166 has a generally cylindrical shaped exterior,and extends from the first end 160 of the intermediate link 128 towardthe second end 162 of the intermediate link 128. According to variousembodiments, the second portion 168 has a generally cylindrically shapedexterior where it contacts the first portion 166, and tapers toward thesecond end 162 of the intermediate link 128. The exterior of the secondportion 168 is configured in the form of a generally segmentedhemisphere. According to various embodiments, the diameter of theintermediate link 128 is on the order of approximately 9.65 millimetersat the first end 160 thereof. The length of the intermediate link 128may be on the order of approximately 8.40 millimeters. However, oneskilled in the art will appreciate that the dimensions of theintermediate link 128 can vary based on the application.

The intermediate link 128 also comprises a first surface 170 thatextends from the first end 160 of the intermediate link 128 to thesecond end 162 of the intermediate link 128, and a second surface 170that extends from the first end 160 of the intermediate link 128 to thesecond end 162 of the intermediate link 128. The first surface 170 maybe considered the outer surface of the intermediate link 128, and thesecond surface 172 may be considered the inner surface of theintermediate link 128. The intermediate link 32 also defines a firstgroove 174 substantially parallel to the longitudinal axis 164 along thesecond surface 172, a second groove 176 substantially parallel to thelongitudinal axis 164 along the second surface 172, and a third groove178 substantially parallel to the longitudinal axis 164 along the secondsurface 172. Each of the first, second and third grooves 174, 176, 178extend along the second surface 172 toward the second end 162 of theintermediate link 128. The first, second and third grooves 174, 176, 178may be semi-tubular shaped and may be evenly spaced about the secondsurface 172 of the intermediate link 128 as shown in FIG. 8C. Accordingto various embodiments, the first, second, and third grooves 174, 176,178 may be configured in the shape of a segmented cylinder. The size ofeach of the grooves 174, 176, 178 may be identical to one another or maybe different from one another. For example, according to variousembodiments, the first and second grooves 174, 176 are configured assegments of cylinders having diameters on the order of approximately1.75 millimeters at the first end 160 of the intermediate link 128, andthe third groove 178 is configured as a segment of a cylinder having adiameter on the order of approximately 2.50 millimeters at the first end160 of the intermediate link 128. The first, second and third grooves174, 176, 178 are each configured to receive and partially surround anyof a variety of tools or instruments (e.g., ablation tools) which maypass from the first end 24 of the multi-linked device 10 to the secondend 26 of the multi-linked device 10.

The intermediate link 128 also defines a passage 180 extending from thefirst end 160 to the second end 162 along the longitudinal axis 164 asshown in FIG. 8B. The passage 180 is of a size sufficient to allow thefirst mechanism 12 to pass therethrough. According to variousembodiments, the passage 180 is generally configured as a complex shapethat comprises a combination of a segmented hemisphere 182 that extendsfrom the first end 160 toward the second end 162, a first segmented cone184 that extends from the segmented hemisphere 182 toward the second end162, a cylinder 186 that extends from the first segmented cone 184toward the second end 162, and a second segmented cone 188 that extendsfrom the cylinder 186 to the second end 162 of the intermediate link128. According to various embodiments, the segmented hemisphere 182represents a portion of a sphere having a diameter on the order ofapproximately 9.65 millimeters, the first segmented cone 184 is taperedat an angle on the order of approximately 15° relative to thelongitudinal axis 164, the cylinder 186 has a diameter on the order ofapproximately 5.50 millimeters, and the second segmented cone 188 istapered at an angle on the order of approximately 15° relative to thelongitudinal axis 164. The segmented hemisphere 182 of the passage 180is configured to receive the second end 132 of the first link 124 whenthe first link 124 is coupled to the intermediate link 128. Similarly,for a given intermediate link 128, the segmented hemisphere 182 of thepassage 180 is configured to receive the second end 162 of anotherintermediate link 128 when the other intermediate link 128 is coupled tothe given intermediate link 128.

The intermediate link 128 also defines a first through-hole 190, asecond through-hole 192, and a third through-hole 194. (See FIG. 8C).The first through-hole 190 is substantially parallel to the longitudinalaxis 164, extends from the first portion 166 toward the second end 162,and is positioned between the passage 180 and the first surface 170. Thesecond through-hole 192 is substantially parallel to the longitudinalaxis 164, extends from the first portion 166 to the second end 162, andis positioned between the passage 180 and the first surface 170. Thethird through-hole 194 is substantially parallel to the longitudinalaxis 164, extends from the first portion 166 to the second end 162, andis positioned between the passage 180 and the first surface 170. Thefirst, second and third through-holes 190, 192, 194 are generallycylindrically shaped. According to various embodiments, thethrough-holes 190, 192, 194 are evenly spaced from one another. The sizeof each of the through-holes 190, 192, 194 may be identical to oneanother or may be different from one another. For example, according tovarious embodiments, the respective diameters associated with thethrough-holes 190, 192, 194 may each be on the order of approximately1.25 millimeters. The first through-hole 190 is configured to receiveand surround a cable. The second through-hole 192 is configured toreceive and surround a cable. The third through-hole 194 is configuredto receive and surround a cable. The first, second and thirdthrough-holes 190, 192, 194 may serve as guidepaths for movement of thecables.

As shown in FIG. 8C, the intermediate link 128 also defines first,second and third indents 196, 198, 200 at the second end 162 thereofresulting, in part, from the combination of the taper associated withthe second portion 168 and the configuration and orientation of thefirst, second, and third grooves 174, 176, 178. The first, second andthird indents 196, 198, 200 may be evenly spaced about the second end162 of the intermediate link 128 as shown in FIG. 8C. The first, secondand third indents 196, 198, 200 may serve to reduce the pinching orbinding of various tools or instruments (e.g., ablation tools) when oneintermediate link 128 of the second mechanism 14 is moved relative toanother intermediate link 128 coupled thereto.

The intermediate link 128 also defines fourth, fifth and sixth indents202, 204, 206 at the second end 162 thereof resulting from thecombination of the taper associated with the second portion 168 and theconfiguration and orientation of the first, second, and thirdthrough-holes 190, 192, 194. The fourth, fifth and sixth indents 202,204, 206 may be evenly spaced about the second end 162 of theintermediate link 128, and may be evenly spaced from the first, secondand third indents 196, 198, 200 as shown in FIG. 8C. The fourth, fifthand sixth indents 202, 204, 206 may serve to reduce the pinching orbinding of the cables when one intermediate link 128 of the secondmechanism 14 is moved relative to another intermediate link 128 coupledthereto.

According to various embodiments, an intermediate link 128 may alsodefine an opening (not shown) that extends from the second surface 172or from one of the grooves 174, 176, 178 to the first surface 170 of theintermediate link 128. The intermediate link 128 may have any number ofsuch openings, and any number of the intermediate links 128 may havesuch openings. Referring to FIGS. 2 and 4, the opening may be utilizedas an exit point for a tool or instrument which may pass from the firstend 24 of the multi-linked device 10 toward the second end 26 of themulti-linked device 10. For such embodiments, the respectiveintermediate link 128 may be positioned proximate to the second link 126of the second mechanism 14. The opening may be oriented at any anglerelative to the longitudinal axis 134 of the intermediate link 128. Whenthe first mechanism 12 is removed from the second mechanism 14, and arelatively large tool or instrument is advanced from the first end 120of the second mechanism 14 to the second end 122 of the second mechanism14, sufficient room may not exist for a second tool or instrument (e.g.,fiber optic cable) to pass through the second end 122 of the secondmechanism 14. For such instances, the second tool or instrument may exitthrough an opening of one of the intermediate links 128.

With the above described structure, the first link 124 may be coupled tothe intermediate link 128 by seating the second end 132 of the firstlink 124 in the segmented hemisphere 182 of the passage 180 of theintermediate link 128. As the convex configuration of the second end 132of the first link 124 generally corresponds with the concaveconfiguration of the segmented hemisphere 182 of the passage 180 of theintermediate link 128, the first link 124 may be coupled to theintermediate link 128 such that the longitudinal axis 134, the first,second and third grooves 142, 144, 146, and the first, second and thirdthrough-holes 154, 156, 158 of the first link 124 are respectivelyaligned with the longitudinal axis 164, the first, second and thirdgrooves 174, 176, 178, and the first, second and third through-holes190, 192, 194 of the intermediate link 128. The intermediate link 128may be moved relative to the first link 124 such that the longitudinalaxis 164 of the intermediate link 128 is not aligned with thelongitudinal axis 134 of the first link 124. According to variousembodiments, the configuration of the first link 124 and theintermediate link 128 allows for the intermediate link 128 to be movedrelative to the first link 124 coupled thereto such that thelongitudinal axis 134 of the first link 124 and the longitudinal axis164 of the intermediate link 128 are up to approximately 10° out ofalignment with one another. Similarly, one intermediate link 128 may becoupled to another intermediate link 128, and so on, by seating thesecond end 162 of one intermediate link 128 in the segmented hemisphere182 of the passage 180 of another intermediate link 128. As the convexconfiguration of the second end 162 of the intermediate link 128generally corresponds with the concave configuration of the segmentedhemisphere 182 of the passage 180 of the intermediate link 128, theintermediate links 128 may be coupled such that the respectivelongitudinal axes 164, the respective first, second and third grooves174, 176, 178, and the respective first, second and third through-holes190, 192, 194 of the intermediate links 128 are aligned. The coupledintermediate links 128 may be moved relative to one another such thatthe respective longitudinal axes 164 of the coupled intermediate links128 are not aligned. According to various embodiments, the configurationof the coupled intermediate links 128 allows for one intermediate link128 to be moved relative to another intermediate link 128 coupledthereto such that the respective longitudinal axes 164 are up toapproximately 10° out of alignment with one another.

FIGS. 9A-9D illustrate various embodiments of the second link 126 (outerdistal link) of the second mechanism 14. The second link 126 includes afirst end 208 and a second end 210, and defines a longitudinal axis 212that passes through the center of the first end 208 and the center ofthe second end 210 as shown in FIG. 9C. The second link 126 may befabricated from any suitable material. According to various embodiments,the second link 126 is fabricated from a thermoplastic material such as,for example, Delrin®.

The second link 126 comprises a first portion 214 and a second portion216. The first portion 214 may be considered the proximal portion andthe second portion 216 may be considered the distal portion. The firstportion 214 may be fabricated integral with the second portion 216. Thefirst portion 214 has a generally cylindrical shaped exterior, andextends from the first end 208 of the second link 126 toward the secondend 210 of the second link 126. According to various embodiments, thediameter of the first portion 214 is on the order of approximately 4.80millimeters.

According to various embodiments, the second portion 216 has a generallycylindrically shaped exterior where it contacts the first portion 214,and tapers toward the second end 210 of the second link 126. Theexterior of the second portion 216 is configured in the form of agenerally segmented cone. According to various embodiments, the exteriorof the second portion 216 tapers from the first portion 214 to thesecond end 210 of the second link 126 at an angle on the order ofapproximately 20° relative to the exterior of the first portion 214. Thelength of the second link 126 may be on the order of approximately 15millimeters. However, one skilled in the art will appreciate that thelength of the second link 126 can vary based on the application.

The second link 126 also comprises a first surface 218 that extends fromthe first end 208 of the second link 126 to the second end 210 of thesecond link 126, and a second surface 220 that extends from the firstend 208 of the second link 126 toward the second end 210 of the secondlink 126. The first surface 218 may be considered the outer surface ofthe second link 126, and the second surface 220 may be considered theinner surface of the second link 126.

The second link 126 also defines a first port 222, a second port 224,and a third port 226. (See FIG. 9B). The first port 222 extends from thesecond surface 220 to the first surface 218 and is substantiallyparallel to the longitudinal axis 212. The second port 224 extends fromthe second surface 220 to the first surface 218 and is substantiallyparallel to the longitudinal axis 212. The third port 226 extends fromthe second surface 220 to the first surface 218 and is substantiallyparallel to the longitudinal axis 212. The first, second and third ports222, 224, 226 may be cylindrical shaped and may be evenly spaced aboutthe longitudinal axis 212 of the second link 126 as shown in FIG. 9D.The size of each of the ports 222, 224, 226 may be identical to oneanother or may be different from one another. For example, according tovarious embodiments, the first and second ports 222, 224 are configuredas cylinders having diameters on the order of approximately 1.50millimeters, and the third port 226 is configured as a cylinder having adiameter on the order of approximately 2.50 millimeters. Otherdimensions are possible. The first, second and third ports 222, 224, 226are each configured to receive and surround any of a variety of tools orinstruments (e.g., ablation tools) which may pass from the first end 24of the multi-linked device 10 to the second end 26 of the multi-linkeddevice 10.

The second link 126 also defines a first through-hole 228, a secondthrough-hole 230, and a third through-hole 232. (See FIG. 9B). The firstthrough-hole 228 extends from the second surface 220 to the firstsurface 218 and is substantially parallel to the longitudinal axis 212.The second through-hole 230 extends from the second surface 220 to thefirst surface 218 and is substantially parallel to the longitudinal axis212. The third through-hole 232 extends from the second surface 220 tothe first surface 218 and is substantially parallel to the longitudinalaxis 212. The first, second and third through-holes 228, 230, 232 aregenerally cylindrically shaped. According to various embodiments, thethrough-holes 228, 230, 232 are evenly spaced from one another as shownin FIG. 9D. The size of each of the through-holes 228, 230, 232 may beidentical to one another or may be different from one another. Forexample, according to various embodiments, the respective diametersassociated with the through-holes 228, 230, 232 may each be on the orderof approximately 1.25 millimeters. The first through-hole 228 isconfigured to receive and surround a cable. The second through-hole 230is configured to receive and surround a cable. The third through-hole232 is configured to receive and surround a cable.

The second link 126 also defines a recess 234 that extends from thefirst end 208 toward the second end 210 along the longitudinal axis 212as shown in FIG. 9C. According to various embodiments, the recess 234 isgenerally configured as a complex shape that comprises a combination ofa first segmented hemisphere 236 that extends from the first end 208toward the second end 210, and a second segmented hemisphere 238 thatextends from the first segmented hemisphere 236 toward the second end210 of the second link 126. According to various embodiments, the firstsegmented hemisphere 236 represents a portion of a sphere having adiameter on the order of approximately 9.50 millimeters, and the secondsegmented hemisphere 238 represents a portion of a sphere having adiameter on the order of approximately 7.0 millimeters. The firstsegmented hemisphere 236 of the recess 234 is configured to receive thesecond end 162 of an intermediate link 128 when the intermediate link128 is coupled to the second link 126.

With the above described structure, an intermediate link 128 may becoupled to the second link 126 by seating the second end 162 of theintermediate link 128 in the first segmented hemisphere 236 of therecess 234 of the second link 126. As the convex configuration of thesecond end 162 of the intermediate link 128 generally corresponds withthe concave configuration of the first segmented hemisphere 236 of therecess 234 of the second link 126, the intermediate link 128 may becoupled to the second link 126 such that the longitudinal axis 164, thefirst, second and third grooves 174, 176, 178, and the first, second andthird through-holes 190, 192, 194 of the intermediate link 128 arerespectively aligned with the longitudinal axis 212, the first, secondand third ports 222, 224, 226, and the first, second and thirdthrough-holes 228, 230, 232 of the second link 126. The second link 126may be moved relative to the intermediate link 128 coupled thereto suchthat the respective longitudinal axes 164, 212 are not aligned.According to various embodiments, the configuration of the second link126 allows for an intermediate link 128 coupled thereto to be movedrelative to the second link 126 such that the respective longitudinalaxes 164, 212 are up to approximately 10° out of alignment with oneanother.

When the first mechanism 12 is inserted into the second mechanism 14,the first second and third grooves 70, 72, 74 of the intermediate links32 of the first mechanism 12 may be substantially aligned with thefirst, second and third grooves 174, 176, 178 of the intermediate links128 of the second mechanism 14, and the first, second and third grooves98, 100, 102 of the second link 30 of the first mechanism 12 may besubstantially aligned with the first, second and third ports 222, 224,226 of the second link 126 of the second mechanism 14. The combinationof the first grooves 70 of the intermediate links 32 of the firstmechanism 12 aligned with the first grooves 174 of the intermediatelinks 128 of the second mechanism 14 allows the respective first grooves70, 174 to collectively serve as a first working port that issubstantially aligned with the first port 222 of the second link 126 ofthe second mechanism 14. The first groove 70 may be considered the innerportion of the first working port and the first groove 174 may beconsidered the outer portion of the first working port.

Similarly, the combination of the second grooves 72 of the intermediatelinks 32 of the first mechanism 12 aligned with the second grooves 176of the intermediate links 128 of the second mechanism 14 allows therespective second grooves 72, 176 to collectively serve as a secondworking port that is substantially aligned with the second port 224 ofthe second link 126 of the second mechanism 14, and the combination ofthe third grooves 74 of the intermediate links 32 of the first mechanism12 aligned with the third grooves 178 of the intermediate links 128 ofthe second mechanism 14 allows the respective third grooves 74, 178 tocollectively serve as a third working port that is substantially alignedwith the third port 226 of the second link 126 of the second mechanism14. The second groove 72 may be considered the inner portion of thesecond working port and the second groove 176 may be considered theouter portion of the second working port. The third groove 74 may beconsidered the inner portion of the third working port and the thirdgroove 178 may be considered the outer portion of the third workingport. The first, second and third working ports may be utilized to passvarious tools or instruments (e.g., ablation tools) from the first end24 of the multi-linked device 10 to the second end 26 of themulti-linked device 10. For the exemplary sizes described hereinabove,the third working port is larger than the first and second workingports. Accordingly, the third working port may be utilized to carry aparticular tool or instrument that is too large to be carried by thefirst or second working ports.

When the respective grooves 70, 72, 74, 174, 176, 178 of the respectiveintermediate links 32, 128 are aligned and collectively surround thevarious tools and instruments, the combination of the grooves 70, 72,74, 174, 176, 178 and the tools and instruments may serve to limit orprevent the rotation of the first mechanism 12 relative to the secondmechanism 14.

As the diameter of the passage 180 of the intermediate link 128 of thesecond mechanism 14 is larger than the diameter of any portion of thefirst mechanism 12, a three-dimensional space 240 exists between thefirst mechanism 12 and the second mechanism 14 when the first mechanism12 is received by the second mechanism 14 (See FIG. 1B). According tovarious embodiments, the space 240 may be utilized to carry wiring,tools, instruments, etc. from the first end 24 of the multi-linkeddevice 10 toward the second end 26 of the multi-linked device 10.

According to various embodiments, one or more steering cables may befabricated from any suitable material. For example, according to variousembodiments, the steering cables may be fabricated from a polyethylenefiber cable such as, for example, Spectra®. The steering cables may beutilized to control the movement of the multi-linked device 10. Forexample, by applying a substantially equal tension to each of thesteering cables, the first mechanism 12 and/or second mechanism 14 maybe steered in a direction such that the respective longitudinal axes 38,62, 90, 134, 164, 212 of each of the links 28, 30, 32, 124, 126, 128 areall aligned. By applying a different tension to one or more of thesteering cables, the first mechanism 12 and/or the second mechanism 14may be steered in a direction such that the respective longitudinal axes38, 62, 90, 134, 164, 212 of each of the links 28, 30, 32, 124, 126, 128are not all aligned. The cables 16, 18, 20 may also be utilized tocontrol the relative state of the second mechanism 14. For example, whena uniform tension is applied to the steering cables, the secondmechanism 14 may be placed in a “rigid” state, and when a tension isremoved from the steering cables, the second mechanism 14 may be placedin a “limp” state. According to various embodiments, one or more of thesteering cables may be attached at the first end 130 of the first link124 of the second mechanism 14 to respective pullies (not shown) by, forexample, respective stopper knots. The steering cables may be attachedto the second end 132 of the second link 126 of the second mechanism 14by, for example, respective stopper knots. One skilled in the art willappreciate that, according to other embodiments, the “rigid” and “limp”states may be achieved by subjecting the first and/or second mechanisms12, 14 to a twisting force, or by any other manner known in the art.

According to various embodiments, one or more tensioning cables may befabricated from any suitable material. For example, according to variousembodiments, the tensioning cables may be fabricated from a polyethylenefiber cable such as, for example, Spectra®. The tensioning cables may beutilized to control the relative state of the first mechanism 12. Forexample, when the tensioning cable is drawn tight, the first mechanism12 may be placed in a “rigid” state, whereas when the tensioning cableis let loose, the first mechanism 12 may be placed in a “limp” state.According to various embodiments, the tensioning cable may be attachedat the first end 34 of the first link 28 of the first mechanism 12 to apully (not shown) by, for example, a stopper knot. The tensioning cablemay be attached to the second end 88 of the second link 30 of the firstmechanism 12 by, for example, a stopper knot.

FIG. 10 illustrates various embodiments of a motion sequence of thesteerable multi-linked device 10. At the start of the sequence, thesecond mechanism 14 surrounds the first mechanism 12 as shown in step“a” of FIG. 10, the longitudinal axes 38, 62, 90 of the links 28, 30, 32of the first mechanism 12 are substantially aligned with the respectivelongitudinal axes 134, 164, 212 of the links 124, 126, 128 of the secondmechanism, and the second end 26 of the first mechanism 12 is atsubstantially the same position as the second end 122 of the secondmechanism 14. A tensioning cable is pulled tight, thereby placing thefirst mechanism 12 in the rigid mode. The steering cables are not pulledtight, thereby placing the second mechanism 14 in the limp mode.

The second mechanism 14 is then advanced so that its second link 126 ispositioned approximately one link ahead of the second end 24 of thefirst mechanism 12 as shown in step “b” of FIG. 10. The cables 16, 18,20 may be utilized to orient the second link 126 to a particularorientation, where the longitudinal axis 134 of the first link 124 is nolonger aligned with the longitudinal axes 164 of the intermediate links128 of the second mechanism 14 or the longitudinal axis 90 of the secondlink 30 of the first mechanism 12. After the second link 126 is in thedesired position and orientation, the steering cables are pulled withidentical force in order to place the second mechanism 14 in the rigidmode, thereby preserving the position and orientation of the secondmechanism 14.

The pulling force of the tensioning cable is then released to place thefirst mechanism 12 in the limp mode. After the first mechanism 12 isplaced in the limp mode, the first mechanism 12 is advanced so that itssecond link 30 is at substantially the same position as the second end122 of the second mechanism 14 as shown in step “c” of FIG. 10. Afterthe second link 30 of the first mechanism 12 is in the desired positionand orientation, the tensioning cable is pulled tight to place the firstmechanism 12 back in the rigid mode, thereby preserving the position andorientation of the first mechanism 12.

The pulling forces of the steering cables are then released to place thesecond mechanism 14 back in the limp mode. After the second mechanism 14is placed back in the limp mode, the second mechanism 14 is advanced sothat its second link 126 is once again positioned approximately one linkahead of the second end 26 of the first mechanism 12 as shown in step“d” of FIG. 10. After the second link 126 is in the desired position andorientation, the steering cables are pulled with identical force inorder to place the second mechanism 14 in the rigid mode, therebypreserving the position and orientation of the second mechanism 14.

The pulling force of the tensioning cable is then released to place thefirst mechanism 12 back in the limp mode. After the first mechanism 12is placed back in the limp mode, the first mechanism 12 is advanced sothat its second link 30 is once again at substantially the same positionas the second end 122 of the second mechanism 14 as shown in step “e” ofFIG. 10. After the second link 30 of the first mechanism 12 is in thedesired position and orientation, the tensioning cable is pulled tightto place the first mechanism 12 back in the rigid mode, therebypreserving the position and orientation of the first mechanism 12. Thegeneral motion sequence described hereinabove, may be repeated anynumber of times, and the second link 126 of the second mechanism 14 maybe advancing in any direction and orientation. One skilled in the artwill appreciate that any number of motion sequences may be utilized withthe multi-linked device 10. For example, according to variousembodiments, the second mechanism 14 may advance any number of linksahead of the first mechanism 12.

The exemplary sizes described hereinabove are generally relative to eachother, and one skilled in the art will appreciate that the multi-linkeddevice 10 can be scaled up or scaled down. For example, although thediameter at the largest portion of the intermediate link 128 of themulti-linked device 10 is on the order of approximately 9.65 millimetersfor the embodiments described hereinabove, one skilled in the art willappreciate that, for other embodiments, the intermediate link 128 can bescaled down such that the diameter at the largest portion of theintermediate link 128 of the multi-linked device 10 is on the order ofapproximately 1.0 millimeter. For such embodiments, each of the othercomponents of the multi-linked device 10 would also be proportionallyscaled down.

The combination of the unique configuration of the respective links 28,30, 32 which comprise the first mechanism 12 and the uniqueconfiguration of the respective links 124, 126, 128 which comprise thesecond mechanism 14 provides the multi-linked device 10 with the abilityto traverse a path defined by the circumference of a circle having arelatively small radius. For example, for the exemplary sizes describedhereinabove, the multi-linked device 10 can traverse a path defined bythe circumference of a circle having a radius on the order ofapproximately 45 millimeters. An example of the multi-linked device 10navigating such tight curvatures is shown in FIG. 11. For embodiments,where the largest portion of the intermediate link 128 of themulti-linked device 10 is on the order of approximately 1.0 millimeter,the multi-linked device 10 can traverse a path defined by thecircumference of a circle having a radius significantly smaller than 45millimeters. One skilled in the art will appreciate that the ability tonavigate such tight curvatures makes the multi-linked device 10 suitablefor use in a number of different minimally invasive procedures, both inluminal spaces and in intracavity spaces.

FIG. 12 illustrates various embodiments of a portion of a steerablemulti-linked device 10. The device 10 may include one or morereinforcing members 302 in contact with at least a portion of one ormore respective intermediate links 128 (outer intermediate link) of thesecond mechanism 14. According to various embodiments, the first link 28may include one or more reinforcing members 302 in contact with at leasta portion of the first link 28. Similarly, the second link 30 mayinclude one or more reinforcing members 302 in contact with at least aportion of the second link 30. In various embodiments, the reinforcingmember 302 may be a circumferentially reinforcing member.

In various embodiments, the reinforcing member 302 may be fabricatedfrom any suitable material. For example, a reinforcing member 302 may befabricated from a polymer thermoplastic material, a mesh, a shrinktubing, a metal, a fiber, etc. According to various embodiments, thereinforcing member 302 may be fabricated from a material comprising aplurality of fibers that may be laminated or otherwise embedded in thematerial. The fibers may be aligned such that they lie in asubstantially circumferential configuration. In various embodiments, thefiber may include a glass, a nylon, etc.

The reinforcing member 302 may be connected to an intermediate link 128,a first link 28 and/or a second link 30 in any suitable manner.According to various embodiments, the reinforcing member 302 may bepress-fit to a first surface 170 of an intermediate link 128 proximatethe first end 160 thereof. According to other embodiments, thereinforcing member 302 may be formed integral with the intermediate link128 proximate the first end 160 thereof. According to variousembodiments, the reinforcing member may be press-fit to a first surface44 of the first link 28. The reinforcing member may be formed integralwith the first link 28. Similarly, the reinforcing member 302 may bepress-fit to a surface of the second link 30. Alternatively, thereinforcing member 302 may be formed integral with the second link 30.

The reinforcing member 302 may be of any suitable size, and may operateto reduce stresses experienced by one or more links when forces areapplied to the cables.

In various embodiments, a reinforcing member 302 may extend from thefirst end 160 of an intermediate link 128 toward the second end 162 ofthe intermediate link 128. The height of a reinforcing member 302 andthe surface area of the intermediate link that is surrounded by thereinforcing member 302 may be dependent on one or more of the thicknessof the reinforcing member 302 and the diameter of the device 10. Forexample, a reinforcing member 302 having a certain thickness maysurround less surface area of an intermediate link 128 than areinforcing member 302 having a smaller thickness. In an embodiment, areinforcing member 302 may surround at least ten percent of the surfacearea of an intermediate link 128. According to various embodiments,reinforcing members 302 on the first link 28 and/or the second link 30may have similar configurations.

According to various embodiments, one or more reinforcing members 302may interfere with the range of motion of a joint. A joint may be thepoint where two adjacent links meet. As such, the one or morereinforcing members 302 may mechanically limit the range of motion of ajoint. FIG. 13 illustrates an exemplary mechanical limit according tovarious embodiments. As illustrated, the wall thickness 1300 of thereinforcing member 302 may be held constant while the longitudinallength 1305 of the reinforcing member 302 may be increased to the pointwhere the reinforcing member 302 interferes with the motion of theadjacent link 1310.

As illustrated by FIG. 14, a similar result may be achieved byincreasing the wall thickness 1400 of a reinforcing member 302 whilekeeping the longitudinal length 1405 of the reinforcing member 302constant. As illustrated, the wall thickness 1400 may be increased tothe point that the reinforcing member may interfere with the motion ofadjacent links 1410.

According to various embodiments, one or more reinforcing members 302may mechanically limit the range of motion of a joint by increasing boththe wall thickness of the reinforcing member and the longitudinal lengthof the reinforcing member 302.

According to various embodiments, one or more reinforcing memberssimilar to the reinforcing member 302 may surround and be in contactwith one or more of the respective intermediate links 32 (innerintermediate link) of the first mechanism 12.

According to various embodiments, one or more reinforcing memberssimilar to the reinforcing member 302 may surround and be in contactwith one or more of the respective intermediate links 128 (outerintermediate link) of the second mechanism 14 and the respectiveintermediate links 32 (inner intermediate link) of the first mechanism12.

While several embodiments of the invention have been described herein byway of example, those skilled in the art will appreciate that variousmodifications, alterations, and adaptations to the described embodimentsmay be realized without departing from the spirit and scope of theinvention defined by the appended claims.

1. A steerable multi-linked device comprising: a first multi-linkedmechanism; and a second multi-linked mechanism, wherein the secondmulti-linked mechanism concentrically surrounds the first multi-linkedmechanism, wherein the first multi-linked mechanism comprises aplurality of links, wherein at least one of the plurality of linkscomprises a reinforcing member.
 2. The device of claim 1, wherein thereinforcing member is connected to a surface of the at least one of theplurality of links.
 3. The device of claim 1, wherein the reinforcingmember is formed integral with the at least one of the plurality oflinks.
 4. The device of claim 1, wherein the reinforcing member is acircumferentially reinforcing member.
 5. The device of claim 1, whereinthe reinforcing member is configured to mechanically limit a range ofmotion of a joint associated with the at least one of the plurality oflinks and an adjacent link.
 6. The device of claim 1, wherein thereinforcing member comprises a metal collar.
 7. The device of claim 1,wherein the reinforcing member is comprised of at least one of: apolymer thermoplastic material; a metal; a fiber; or a mesh.
 8. Asteerable multi-linked device comprising: a first multi-linked mechanismcomprising a first plurality of links, wherein at least one of the firstplurality of links comprises a first reinforcing member; and a secondmulti-linked mechanism comprising a second plurality of links, whereinat least one of the second plurality of links comprises a secondreinforcing member, wherein the second multi-linked mechanismconcentrically surrounds the first multi-linked mechanism.
 9. The deviceof claim 8, wherein the first reinforcing member is connected to asurface of the at least one of the first plurality of links.
 10. Thedevice of claim 8, wherein the second reinforcing member is connected toa surface of the at least one of the second plurality of links.
 11. Thedevice of claim 8, wherein the first reinforcing member is formedintegral with the at least one of the first plurality of links.
 12. Thedevice of claim 8, wherein the second reinforcing member is formedintegral with the at least one of the second plurality of links.
 13. Thedevice of claim 8, wherein one or more of the first reinforcing memberand the second reinforcing member is a circumferentially reinforcingmember.
 14. The device of claim 8, wherein the first reinforcing memberis configured to mechanically limit a range of motion of a jointassociated with the at least one of the first plurality of links. 15.The device of claim 8, wherein the second reinforcing member isconfigured to mechanically limit a range of motion of a joint associatedwith the at least one of the second plurality of links.
 16. The deviceof claim 8, wherein one or more of the first reinforcing member and thesecond reinforcing member comprises a metal collar.
 17. The device ofclaim 8, wherein one or more of the first reinforcing member and thesecond reinforcing member is comprised of at least one of: a polymerthermoplastic material; a metal; a fiber; or a mesh.